摘要:
Implementations relate to systems and methods for generating compensated speed values for a Doppler-enabled device. A portable wireless device can contain a GPS navigation engine (110) to capture position data (120) and Doppler speed data (118) from positioning satellites. The device can also generate position-based speed values from successive position readings and time intervals, to determine the current speed independently of the Doppler-based speed values. During degraded signal conditions, the Doppler-based speed values can drop to invalid levels. The device incorporates a combiner module (450) which compares the position-based and Doppler-based speed values and performs combination operations on those quantities to produce a compensated speed value (490). By selecting the maximum or otherwise combining those values, extreme excursions in speed values are avoided and accuracy promoted.